Common Bullfrog — Part 3

Rana catesbiana Shaw

If we go rowing on river, lake, or park lagoon some moonlight night in late June, we are certain to hear the deep-toned call of the Bullfrog many times. Coming as it does at unexpected intervals and from unexpected directions, it seems startlingly weird in the quiet of the night. For June nights are quiet. The insect orchestras are not yet in full swing and the frog choruses have disbanded. The toads are still calling, though much more feebly than earlier in the season, and the voices of only a few can be heard, whereas there were hundreds in May. The Bullfrog does not sing in chorus; the call is an isolated one. The notes are so low in pitch that we think of him as the bass viol among the batrachia. The call resembles, to a considerable degree, the roar of a distant bull, but it has a more musical ring, and the notes are less blended and slurred. The pitch varies with the individual. The following are four interesting annotations of the bullfrog's call: (Familiar Life in Field and Forest. F. Schuyler Matthews. D. Appleton & Co.)

The call can be imitated well by saying with a hoarse, deeptoned voice the syllables of various interpretations of it, such as, "Be drowned," Better go round," "Jug o' rum," or "More rum." The imitation is especially good if the slurred words are repeated in front of some reverberating hollow body. That the call has a musical quality was once illustrated most ludicrously. During the rehearsal of a chorus of female voices, a big yellow-throated Bullfrog, in an adjoining room, began vigorously ejaculating, "Jug o' rum, jug o' rum., jug o' rum " Several persons were deceived for the moment into thinking that the bass voice of the director had joined the chorus, for it happened that the first few notes of the frog were in time and harmony with the chords of the selection. A tame Bullfrog will always sing when other sounds are being produced, whether these are musical or not. He always becomes enthusiastic at the sound of running water.

The Bullfrog has two internal vocal sacs, which act as resonators. These are in the pouch of the throat, and the openings into them are on the floor of the mouth. When the frog croaks, the yellow throat over the vocal sacs, and the sides of the body in the region of the lungs, are forcibly distended with air drawn in through the nostrils. Throat and sides immediately relax as the air passes out over the vocal cords of the throat and the sound is produced.

The frog's vocal powers do not stop with the croaking described. If we live in the country, or if we are given to camping and fishing, it is possible that at least once in a lifetime we shall hear this species of frog give voice to quite another sound. This comes when he is forcibly seized by a huge enemy, such as a hawk or an otter. The unexpected sound given at such a time is most distressing to hear. It is a loud, prolonged, high-pitched scream, containing anguish and antagonism, to such an extent that we cannot but think that the cry is made by the human voice. Sometimes, when we take into our hands a masterful, untamed Bullfrog, just brought from the pond, he gives this same cry with wide-opened mouth. The scream of distress is so penetrating, and so prolonged, that we hasten to release the frog, for fear our neighbours will accuse us of cruelty to children.

However, as the mouth is held wide open while the cry is given, we find a most excellent opportunity to see various things about which we may have been curious. The tongue has a forked posterior end, and has its front end fastened just back of the lower lip. (See description of toad's tongue, p. 8r.) There is a circle of small, sharp teeth on the upper jaw. Two large openings at the sides back of the tongue lead into the vocal sacs. Two smaller openings on the roof of the mouth are the openings of the tubes leading from the nostrils. Their situation so far in front of the throat makes it clear why it is that the frog must swallow the air that passes in at the nostrils in order to get it down to the lungs. The great rounded elevations on the roof of the mouth are made by the eyes. These extensions from the roof of the mouth appear when the eyes are flattened to a level with the top of the head.